One particular case of a high-speed satellite telecommunications system is that of a telecommunications system based on a constellation of regenerative satellites and capable of switching DVB-S2 frames such as defined in the ETSI (European Telecommunications Standard Institute) standard with the reference EN 302 307 V1.1.2 (2006-06) and entitled “Digital Video Broadcasting (DVB); Second generation framing structure, channel coding and modulation systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications”. This telecommunications system is described in the patent application entitled “Method for the very-high-speed transparent routing of data packets in a spaceborne telecommunications system using a network of regenerative satellite with ISLs”, filed jointly with the present application.
The only solution at present, known and described in the ETSI standard EN 302 307 V1.1.2 (2006-06), for optimizing the spectral resources of a DVB-S2 frame transfer is to use a local adaptive coding and modulation (ACM) loop per link between a ground station and a satellite.
The use of such a local method leads to different modulation-coding parameter pairs on the two links formed by a first link between a first station and a first satellite on the one hand, and by a second link between a second satellite and a second station on the other hand. The use thereof in the case of DVB-S2 frame switching involves the implementation of segmentation solutions at the level of the GSE (generic stream encapsulation protocol) encapsulation layer or concatenation solutions at the level of the frames, leading, for the high speeds in question, to processing operations which are complex to perform.
Furthermore, in the case of high-speed links, this optimization based on the use of one ACM loop per (sending/receiving) ground station—(sending/receiving) on-board satellite link may also lead to substantial data losses in the buffer memories of the receiving satellite serving the receiving station if the budget of the corresponding downlink is unfavourable, along with an increase in the spectral efficiency that is not used in the case of an access with a single carrier per channel per carrier (SCPC) if the budget of the uplink between the sending station and the sending satellite is unfavourable.
The technical problem is to improve the performance, in terms of optimizing the spectral resources, of a very-high-speed end-to-end transport of data services, routed from a sending station to a receiving station via a packet-switching regenerative spaceborne satellite network, and to limit the on-board complexity of the equipment on-board the satellites allowing the switching of the data packets.
This technical problem is to be solved in particular in the case of transporting frames using the DVB-S2 protocol.